Water hardness

Rainwater is initially soft. Water hardness only occurs when water passes through soils and/or aquifers. It therefore depends heavily on the geological subsoil as to which and how much hardness constituents can dissolve.

In contrast to the nitrate content, there is no fixed limit value for water hardness in Germany.

Water hardness has advantages and disadvantages, but no health risks.

Soft water, for example, does not cause appliances to calcify as quickly, but does lead to more foaming with cleaning agents.

Hard water, on the other hand, leads to faster calcification of household appliances and increases the consumption of washing-up liquid and detergents.
Hard water usually comes from regions where sand and limestone predominate.

In most European countries, water hardness is categorised into 3 hardness ranges:

Soft with a hardness of up to 8,4 °dH (<1,5 mmol/l)
Medium with a water hardness ofn 8,4-14 °dH (1,5-2,5 mmol/l)
Hard with a water hardness above 14 °dH (> 2,5 mmol/l)

At the same time, the total hardness per litre (°dH, °fH, °e) was replaced by the unit of measurement Millimoles of calcium carbonate per litre (mmol/l).
Damit sollten die Härtebereiche an die europäischen Standards angepasst werden.

Breakdown of water hardness

On our map you can view the hardness range for each water supply zone or city covered.

Based on the different areas shown in colour on the map, the following is an example for Germany Distribution of water hardness in Germany (as at 6/2024)

0 - 8,4 °dH (1,5 mmol/l - soft) 8,5 - 14 °dH (medium) >14 °dH (2,5 mmol/l - hard)

37%

29%

34%

What is affected by water hardness?

The best known are certainly the water softeners contained in detergents. The harder the water, the more softener is required: More detergent needs to be added. Depending on the manufacturer, this can even double the amount required. This is not only a burden on your wallet, but of course also on the environment. Especially when this overdosing would not even be necessary with soft water.

According to the German Federal Environment Agency, around 630,000 tonnes of detergent are used in Germany every year, which equates to around 15 kilograms of detergent per household in around 41 million households. If every household followed the manufacturer's recommendation on water hardness when dosing, how much would be saved?

After all, who hasn't experienced this: when dosing, sometimes a little more, sometimes a little less detergent is used by feel. Depending on how full the machine is or how dirty the laundry appears. Most of the time, however, too much However, as the Öko-Institut found in a study for the Miele company back in 2008, the dosage is usually too high. The study came to the conclusion that a household in Germany uses around 3.5 kg of detergent too much. This did not take into account the different levels of water hardness.

145 thousand tonnes

Detergents are used TOO MUCH every year in Germany alone and released into the environment!

3.5 kg of unnecessarily used detergent per year equates to around 5-15 euros in additional costs per household, depending on the detergent. Admittedly, this is a manageable cost factor. For the environment, however, this means that with around 41 million households in Germany, 145,000 tonnes of unnecessary detergent end up in the waste water every year.